Variable resistor with collector and grounding contact

ABSTRACT

A tab is connected to a mounting plate for a control means, the tab terminating at a predetermined position along a resistive path of the control means to provide selective positioned grounding of the contact arm.

United States Patent Puerner 51 Sept. 12, 1972 [54] I VARIABLE RESISTOR WITH COLLECTOR AND GROUNDING CONTACT Inventor:

Assi gnee:

Filed:

Appl. No.:

US. Cl Int. Cl.

George 0. Puerner, Frankford, nsitifillefi [56] References Cited UNITED STATES PATENTS 2,898,567 8/1959 Drewitz ..338/l37 X 3,184,696 5/1965 Snyder ..338/l74 Pn'mary Examiner-Lewis H. Myers Assistant Examiner-Gerald P. Tolin Attorney-Richard H. Childress et al.

Oct. 27, 1971 192,908 ABSTRACT A tab is connected to a mounting plate for a control H 338/174 338/197 means, the tab terminating at a predetermined posiiiolc 9/02 tion along a resistive path of the control means to pro- Field of 172474 vide selective positioned grounding of the contact 4 Claims, 2 Drawing Figures i 36 l j l 34 VARIABLE RESISTOR WITH COLLECTOR AND GROUNDING CONTACT This invention relates to a control means and more particularly to a grounding means for a variable resistor.

Control means such as variable resistors find many uses in radios, steros, TVs, and similar appliances to regulate the volumne or the output of the appliance. While the resistor case or housing may be electrically grounded, normally the electrical contact arms are not. Depending upon a particular application, for example in car radios, it may be desirable to selectively electrically ground the resistor contact arm.

The present invention is concerned with a control unit such as a variable resistor and has as one of its objects the provision of an electrical ground means for selectively grounding the contact arm of the resistor.

Another object of the invention is the provision of a control unit having an electrical ground means extending from the mounting plate of the unit.

Still another object of the invention is the provision of a control unit having an electrical ground tab connected to a mounting plate of the unit and terminating juxtaposition an end of a resistive path for the unit.

These and other objects of the invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a top view of a control unit employing the principles of the invention;

FIG. 2 is a section taken along the lines 2-2 of FIG. 1'.

Generally speaking, the objects of the invention are accomplished by providing in combination a control means comprising a resistive path and a collector path, electrical terminals connected to the paths, a rotor carried by a shaft, electrical contacts carried by the rotor and engaging the paths; a mounting plate carrying the control means; and an electrical ground tab connected to the mounting plate and terminating juxtaposition an end of the resistive path.

Referring now to the drawings, there is shown a control means such as a variable resistor 10 employing the principles of the invention. A typical variable resistor includes a shaft 12 rotatably journalled in a bushing 14 and a cup shaped housing member 16. The cup shaped housing member 16 is closed by a base 18. Base 18 carries a resistive path 20 and a ground ring 22. Resistive path 20 is provided by a carbon strip 20' carried on a base 21. An electrical terminal 24 is electrically connected to the ground ring 22 while at least one of the electrical terminals 26 or 28 are electrically connected to the resistive path 20. A rotor 30 is fixedly carried by the shaft 12. Rotor 30 carries a contact arm 32 which engages the resistive path and the collector path. Rotation of shaft 12 rotates the contact arm around the resistive path to vary the electrical resistance. If desired, such rotation may be limited by a stop plate 34 carried by the shaft 12 which engages a stop lug 36 lanced from the cup shaped member 16.

According to the present invention a contact arm of a variable resistor such as is just described is grounded by providing an electrical ground tab 38 lanced or otherwise connected to the variable resistor mounting plate 40. The tab extends through an aperture 42 of the resistive path in a notch 46 provided at the end of the path. It s ould be understood that the tab may be exposed or positioned at various positions along or at either end of the resistive path. The contact arm may now be grounded at the end of its rotation merely by engaging the contact arm with the ground tab 38.

What is claimed is:

1. In combination, control means comprising a resistive path and a collector path, electrical terminals connected to said paths, a rotor carried by a shaft, electrical contacts carried by said rotor and engaging said paths; a mounting plate carrying said control means; and an electrical ground tab connected to said mounting plate and terminating at a predetermined position in line with said resistive path.

2. The combination according to claim 1 wherein said electrical ground tab includes a tab lanced from said mounting plate.

3. The combination according to claim 1 wherein said mounting plate is carried by a bushing into which said shaft is rotatably journalled.

4. In combination:

1. a variable resistor comprising:

a. a cup shaped member,

b. a base member closing said cup-shaped member,

c. a resistance path and a collector path carried inside said cup-shaped member and on said base member, electrical terminals connected to said paths,

d. a rotatable shaft extending through said base member into said cup-shaped member,

e. a rotor carried by said shaft, and electrical contact arms engaging said resistive path and said collector paths,

2. a mounting plate connected to said base member,

and

3. an electrical ground tab connected to said mounting plate extending through said base member and terminating juxtaposition an end of said resistive path. 

1. In combination, control means comprising a resistive path and a collector path, electrical terminals connected to said paths, a rotor carried by a shaft, electrical contacts carried by said rotor and engaging said paths; a mounting plate carrying said control means; and an electrical ground tab connected to said mounting plate and terminating at a predetermined position in line with said resistive path.
 2. The combination according to claim 1 wherein said electrical ground tab includes a tab lanced from said mounting plate.
 2. a mounting plate connected to said base member, and
 3. an electrical ground tab connected to said mounting plate extending through said base member and terminating juxtaposition an end of said resistive path.
 3. The combination according to claim 1 wherein said mounting plate is carried by a bushing into which said shaft is rotatably journalled.
 4. In combination: 